.TH std::negative_binomial_distribution 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::negative_binomial_distribution \- std::negative_binomial_distribution

.SH Synopsis
   Defined in header <random>
   template< class IntType = int >        \fI(since C++11)\fP
   class negative_binomial_distribution;

   Produces random non-negative integer values i, distributed according to discrete
   probability function:

   \\(P(i|k, p) = \\binom{k + i - 1}{i} \\cdot p^k \\cdot (1 - p)^i\\)P(i|k,p) =⎛
   ⎜
   ⎝k + i − 1
   i⎞
   ⎟
   ⎠ · pk
   · (1 − p)i

   The value represents the number of failures in a series of independent yes/no trials
   (each succeeds with probability p), before exactly k successes occur.

   std::negative_binomial_distribution satisfies RandomNumberDistribution.

.SH Template parameters

             The result type generated by the generator. The effect is undefined if
   IntType - this is not one of short, int, long, long long, unsigned short, unsigned
             int, unsigned long, or unsigned long long.

.SH Member types

   Member type         Definition
   result_type \fI(C++11)\fP IntType
   param_type \fI(C++11)\fP  the type of the parameter set, see RandomNumberDistribution.

.SH Member functions

   constructor   constructs new distribution
   \fI(C++11)\fP       \fI(public member function)\fP
   reset         resets the internal state of the distribution
   \fI(C++11)\fP       \fI(public member function)\fP
.SH Generation
   operator()    generates the next random number in the distribution
   \fI(C++11)\fP       \fI(public member function)\fP
.SH Characteristics
   p             returns the distribution parameters
   k             \fI(public member function)\fP
   \fI(C++11)\fP
   param         gets or sets the distribution parameter object
   \fI(C++11)\fP       \fI(public member function)\fP
   min           returns the minimum potentially generated value
   \fI(C++11)\fP       \fI(public member function)\fP
   max           returns the maximum potentially generated value
   \fI(C++11)\fP       \fI(public member function)\fP

.SH Non-member functions

   operator==
   operator!=                compares two distribution objects
   \fI(C++11)\fP                   \fI(function)\fP
   \fI(C++11)\fP(removed in C++20)
   operator<<                performs stream input and output on pseudo-random number
   operator>>                distribution
   \fI(C++11)\fP                   \fI(function template)\fP

.SH Example


// Run this code

 #include <iomanip>
 #include <iostream>
 #include <map>
 #include <random>
 #include <string>

 int main()
 {
     std::random_device rd;
     std::mt19937 gen(rd());
     // Pat goes door-to-door selling cookies
     // At each house, there's a 75% chance that she sells one box
     // how many times will she be turned away before selling 5 boxes?
     std::negative_binomial_distribution<> d(5, 0.75);

     std::map<int, int> hist;
     for (int n = 0; n != 10000; ++n)
         ++hist[d(gen)];

     for (auto [x, y] : hist)
         std::cout << std::hex << x << ' ' << std::string(y / 100, '*') << '\\n';
 }

.SH Possible output:

 0 ***********************
 1 *****************************
 2 **********************
 3 *************
 4 ******
 5 ***
 6 *
 7
 8
 9
 a
 b

.SH External links

   Weisstein, Eric W. "Negative Binomial Distribution." From MathWorld — A Wolfram Web
   Resource.
